As disclosed in U.S. Pat. No. 3,170,202, the concept of using an explosion process for the manufacturer of molds and cores for the foundry industry is broadly known. In that patent, it is suggested that the mold material can be packed by the explosion-like combustion of a fuel over the mold material in a closed system. However, the technique disclosed therein has the disadvantage that the results produced by the disclosed technique are not reproducible. Additionally, the ultimate force values necessary for foundry purposes cannot be attained with that system without the use of additional oxygen. Thus, the technique is, as a practical matter, not satisfactory.